Chronic lymphocytic leukaemia (CLL)

A 68-year-old man presents with fatigue, weight loss, night sweats, and recurrent infections. Blood tests show:

• Hb: 9 g/dL
• WBC: 98 × 10⁹/L
• Platelets: 180 × 10⁹/L
• Blood film: Smudge cells

What is the most likely diagnosis?

A) Chronic myeloid leukaemia (CML)
B) Chronic lymphocytic leukaemia (CLL)
C) Acute myeloid leukaemia (AML)
D) Acute lymphoblastic leukaemia (ALL)
E) Multiple myeloma

Correct Answer:

B) Chronic lymphocytic leukaemia (CLL)

Explanation:

CLL is a B-cell malignancy seen in older adults with:

• Massive leukocytosis (↑ WBC)
• Smudge cells on blood film (fragile lymphocytes)
• Recurrent infections (due to immune dysfunction)
• A) CML → Incorrect. Associated with BCR-ABL (Philadelphia chromosome) and low LAP score.
• C) AML → Incorrect. Presents suddenly with pancytopenia, gum hypertrophy, and Auer rods.
• D) ALL → Incorrect. Common in children, presents with bone pain, hepatosplenomegaly, and CNS symptoms.
• E) Multiple myeloma → Incorrect. Associated with hypercalcaemia, renal failure, bone pain, and monoclonal protein.

Key Tips for PLAB 1:

✅ Smudge cells + high WBC = CLL.
✅ Complications: Autoimmune haemolysis, Richter transformation.
✅ Treatment: Observation if asymptomatic; chemotherapy (fludarabine, rituximab) if symptomatic.